August is one of the warmer months of the year in Cornwall, with average highs near 25.5°C and lows around 14.8°C (mean 20.2°C). It is a relatively wet time of year, averaging 92 mm of rainfall and 77% relative humidity across the period.
August is one of the warmer months of the year in Cornwall. Across 45 years of records, the warmest August in Cornwall was 2021 — when the month averaged 24.1°C — while the coldest was 1982 at 17°C. Typical August days reach 25.5°C with nights near 14.8°C. The long-term trend is warming, about 0.6°C per decade.
August is a relatively wet time of year in Cornwall, averaging 92 mm of rainfall. The wettest August on record was 1981 with 145 mm, while the driest was 2002 at 31 mm.
Relative humidity in Cornwall during August averages 77%. The most humid August was 2000 at 83%, and the least humid was 2025 at 63%.
August receives about 5.1 kWh/m²/day of solar energy in Cornwall. The sunniest Augusts were 1996 and 2002 at 5.6 kWh/m²/day, and the cloudiest was 1988 at 4.3.
Average wind speed in Cornwall during August is 0.4 m/s. The windiest August was 1987 at 0.5 m/s, while the calmest were 2023, 2024 and 2025, among others at 0.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 19.0°C | 19.6°C | 20.3°C | 20.8°C | 21.6°C | +2.6°C |
| Avg High | 24.3°C | 24.8°C | 25.5°C | 26.2°C | 27.2°C | +2.9°C |
| Avg Low | 13.6°C | 14.3°C | 15.0°C | 15.5°C | 15.9°C | +2.3°C |
| Avg Rain | 110 mm | 88 mm | 84 mm | 89 mm | 91 mm | -19 mm |
August temperatures in Cornwall have risen by about 2.6°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 4.5°C (1982) to a record high of 36.2°C (2025).
Rainfall in August is a relatively wet time of year, averaging 92 mm, with a wettest year of 145 mm.
One of the best times to visit Cornwall
August is one of the best times to visit Cornwall. Expect days averaging 25.5°C and nights around 14.8°C (mean 20.2°C) — warmer than Cornwall's yearly average — with higher rainfall (92 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 28.0°C | 21.5°C | 15.0°C | 36.2°C | 9.5°C | 47 mm | 63% | 0.4 m/s | 5.3 |
| 2024 | 25.4°C | 20.4°C | 15.3°C | 31.8°C | 9.9°C | 143 mm | 79% | 0.4 m/s | 4.5 |
| 2023 | 25.4°C | 19.9°C | 14.3°C | 28.6°C | 8.2°C | 95 mm | 75% | 0.4 m/s | 4.8 |
| 2022 | 28.0°C | 22.3°C | 16.7°C | 34.7°C | 11.6°C | 100 mm | 72% | 0.4 m/s | 5 |
| 2021 🔥 | 29.7°C | 24.1°C | 18.5°C | 34.6°C | 12.8°C | 46 mm | 69% | 0.4 m/s | 5 |
| 2020 | 26.7°C | 21.3°C | 15.9°C | 32.6°C | 9.6°C | 113 mm | 72% | 0.4 m/s | 5.2 |
| 2019 | 25.8°C | 20.1°C | 14.5°C | 29.7°C | 10.4°C | 67 mm | 75% | 0.4 m/s | 5.4 |
| 2018 | 27.3°C | 22.2°C | 17.1°C | 31.3°C | 10.9°C | 71 mm | 79% | 0.4 m/s | 4.9 |
| 2017 | 23.9°C | 19.2°C | 14.4°C | 28.6°C | 7.7°C | 82 mm | 81% | 0.4 m/s | 5.3 |
| 2016 | 29.0°C | 23.2°C | 17.4°C | 35.5°C | 11.1°C | 92 mm | 69% | 0.4 m/s | 5.2 |
| 2015 | 27.0°C | 21.4°C | 15.8°C | 32.3°C | 11.8°C | 74 mm | 71% | 0.4 m/s | 4.9 |
| 2014 | 24.5°C | 19.3°C | 14.2°C | 30.3°C | 9.6°C | 103 mm | 79% | 0.4 m/s | 5.1 |
| 2013 | 25.1°C | 19.9°C | 14.6°C | 30.0°C | 8.1°C | 83 mm | 78% | 0.4 m/s | 5.1 |
| 2012 | 28.1°C | 22.1°C | 16.2°C | 34.5°C | 9.8°C | 65 mm | 68% | 0.4 m/s | 5 |
| 2011 | 24.8°C | 20.0°C | 15.1°C | 28.6°C | 10.4°C | 117 mm | 81% | 0.4 m/s | 5 |
| 2010 | 26.1°C | 20.6°C | 15.2°C | 31.9°C | 9.3°C | 133 mm | 76% | 0.4 m/s | 5.1 |
| 2009 | 24.9°C | 20.2°C | 15.5°C | 30.6°C | 7.3°C | 97 mm | 81% | 0.4 m/s | 5 |
| 2008 | 24.1°C | 19.1°C | 14.0°C | 29.7°C | 8.4°C | 84 mm | 81% | 0.4 m/s | 5.1 |
| 2007 | 25.6°C | 19.9°C | 14.1°C | 31.2°C | 8.0°C | 61 mm | 76% | 0.4 m/s | 5.4 |
| 2006 | 24.3°C | 19.3°C | 14.2°C | 32.6°C | 7.4°C | 72 mm | 77% | 0.4 m/s | 5.5 |
| 2005 | 27.1°C | 21.6°C | 16.2°C | 31.3°C | 9.3°C | 93 mm | 74% | 0.4 m/s | 5.1 |
| 2004 | 23.7°C | 18.7°C | 13.8°C | 28.5°C | 8.2°C | 118 mm | 82% | 0.4 m/s | 4.7 |
| 2003 | 26.5°C | 21.4°C | 16.4°C | 32.0°C | 8.8°C | 85 mm | 79% | 0.4 m/s | 4.9 |
| 2002 | 26.8°C | 21.1°C | 15.5°C | 32.6°C | 10.3°C | 31 mm | 74% | 0.4 m/s | 5.6 |
| 2001 | 28.2°C | 22.3°C | 16.3°C | 34.2°C | 9.6°C | 87 mm | 69% | 0.4 m/s | 5.2 |
| 2000 | 23.8°C | 19.0°C | 14.3°C | 28.0°C | 8.6°C | 112 mm | 83% | 0.4 m/s | 4.7 |
| 1999 | 25.1°C | 19.7°C | 14.2°C | 31.3°C | 9.4°C | 54 mm | 72% | 0.4 m/s | 5 |
| 1998 | 25.0°C | 20.3°C | 15.6°C | 31.1°C | 8.3°C | 90 mm | 81% | 0.4 m/s | 5 |
| 1997 | 23.2°C | 18.1°C | 13.0°C | 29.0°C | 8.2°C | 106 mm | 79% | 0.4 m/s | 5 |
| 1996 | 24.4°C | 19.3°C | 14.2°C | 29.2°C | 8.5°C | 65 mm | 81% | 0.4 m/s | 5.6 |
| 1995 | 26.9°C | 20.6°C | 14.4°C | 32.2°C | 8.7°C | 89 mm | 72% | 0.4 m/s | 5.4 |
| 1994 | 23.5°C | 18.3°C | 13.0°C | 28.5°C | 7.4°C | 92 mm | 80% | 0.4 m/s | 5.2 |
| 1993 | 25.2°C | 20.2°C | 15.3°C | 29.8°C | 9.8°C | 78 mm | 81% | 0.4 m/s | 5.2 |
| 1992 | 23.3°C | 18.3°C | 13.2°C | 29.0°C | 8.4°C | 100 mm | 80% | 0.4 m/s | 4.7 |
| 1991 | 26.1°C | 20.6°C | 15.1°C | 31.2°C | 9.0°C | 93 mm | 76% | 0.4 m/s | 5 |
| 1990 | 25.7°C | 20.2°C | 14.7°C | 31.0°C | 8.7°C | 114 mm | 80% | 0.4 m/s | 5.2 |
| 1989 | 24.0°C | 18.7°C | 13.4°C | 29.2°C | 5.2°C | 109 mm | 77% | 0.4 m/s | 5.2 |
| 1988 | 26.1°C | 20.7°C | 15.3°C | 34.5°C | 7.3°C | 123 mm | 76% | 0.4 m/s | 4.3 |
| 1987 | 24.1°C | 18.5°C | 12.9°C | 31.5°C | 7.2°C | 60 mm | 74% | 0.5 m/s | 5 |
| 1986 | 22.7°C | 17.7°C | 12.7°C | 29.1°C | 4.6°C | 143 mm | 82% | 0.4 m/s | 4.8 |
| 1985 | 23.8°C | 18.4°C | 12.9°C | 29.6°C | 8.3°C | 73 mm | 75% | 0.4 m/s | 4.8 |
| 1984 | 26.2°C | 20.8°C | 15.5°C | 35.5°C | 7.2°C | 132 mm | 79% | 0.4 m/s | 5.1 |
| 1983 | 25.3°C | 20.0°C | 14.6°C | 31.7°C | 7.7°C | 98 mm | 77% | 0.4 m/s | — |
| 1982 ❄️ | 22.4°C | 17.0°C | 11.5°C | 27.3°C | 4.5°C | 107 mm | 77% | 0.4 m/s | — |
| 1981 🌧️ | 24.0°C | 18.8°C | 13.6°C | 30.4°C | 7.9°C | 145 mm | 81% | 0.4 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 25.5°C with lows near 14.8°C (mean 20.2°C), based on 45 years of NASA POWER data.
August averages 92 mm of rainfall in Cornwall, a relatively wet time of year. The wettest on record was 145 mm in 1981.
The hottest August reached 36.2°C in 2025. The coldest dipped to 4.5°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 2.6°C. Daytime highs moved from 24.3°C to 27.3°C and overnight lows from 13.6°C to 16°C over the same span.
August is one of the warmer months of the year in Cornwall and a relatively wet time of year, so plan for around 25.5°C daytime highs and 14.8°C at night.
Not quite — August is the 11th coolest month in Cornwall, averaging 20.2°C.
For August in Cornwall, pack light layers you can adjust through the day, with typical highs of 25.5°C and lows of 14.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 77% — quite humid.
Average wind speed in August is 0.4 m/s. The windiest August on record averaged 0.5 m/s (1987).
The wettest August on record was 1981 with 145 mm. On average, August sees 92 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Cornwall behaves each August, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for August specifically, along with year-by-year records and how the month has changed over the decades.
